Tow dolly for wheeled vehicles

ABSTRACT

A tow dolly for wheeled vehicles of the type embodying a chassis having a pair of arms converging as a trailer tongue at its forward end and supporting an axle and pair of wheels at its aft end. The chassis includes a pair of towed vehicle wheel ramps pivoted to act as a ramp for loading of the towed vehicle front wheels onto the chassis and configured to confine the front wheels during towing. The structure distinguishes from the prior art in combining these features with surge braking and linked steering mechanisms for turning the two dolly wheels as the towing vehicle turns, as well as a compression means damping the pivoting of the wheel ramp during loading and towing.

United States Patent [72] Inventors Filed Patented Assignee 6 Claims, 7Drawing Figs.

bodying a chassis having a pair of am'is converging as a trailer [52]US. Cl 214/85, tongue at its forward end and Supporting an l d nf214/334, 280/463, 280/M'3 wheels at its aft end. The chassis includes apair of towed vehi- [51] Int. Cl B60p 1/44 cle wheel ramps pivoted toact as a ramp for loading f the [50] Field of Search 214/85, towedvehide from wheels onto the chassis and configured to 505, 506, 334;280/463, 468, 4 86 A confine the front wheels during towing. Thestructure distin- 56 R f d guishes from the prior art in combining thesefeatures with l 1 e erences l e surge braking and linked steeringmechanisms for turning the UNITED STATES PATENTS two dolly wheels as thetowing vehicle turns, as well as a com- 1,230,326 6/1917 Puderbaugh214/334 pression means damping the pivoting of the wheel ramp dur-1,819,625 8/1931 Schroeder 214/505 ing loading and towing.

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/d 2 H fl/ Appl. No.

James W. Ryden Phoenix;

John C. Abromavage, Tempe, both of Ariz.

TOW DOLLY FOR WHEELED VEHICLES Primary ExaminerAlbert J. MakayAttorney-David H. Semmes ABSTRACT: A tow dolly for wheeled vehicles ofthe type em- PATENTEnum 19 l97l SHEET 1 BF 3 TOW DOLLY FOR WHEELEDVEHICLES BACKGROUND OF THE INVENTION 1. Field of the Invention Thisinvention concerns rescue towing of disabled vehicles or towing ofvehicles which are required to be transported without a drive,particularly, a wheeled trailer or dollywhich can be readily connectedto a towing'vehicle, towed to the vehicleto be moved,-and readily loadedwith this vehicle for towing to repair or service. The device eliminatesthe necessity for capital investment in the conventional wrecking ortowing truck and can easily be handled by an inexperienced operator.

2. The Prior Art Prior art searching has developed the following:

Rodin 2,210,007 Hunt 2,3l2,646 Whitlow 2,559,487 Averette 2,561,644Pankonin 2,695,| 8| Henry 2,750,208 Lorr 2,797,l06 lsachsen 2,974,978Mannheim 3,06l ,020 Bigge 3,l$6,487 Lemmon 3,322,439

The prior art teaches the employment of trailers attachable to a towingvehicle automobile bumper or hitch bars. These trailers include asteering bar and like mechanisms for turning the trailer wheels upon thetrailer.

However, the prior art does not suggest the combination of a wheeled towdolly with surge brake and steering mechanisms, as well as shocksinterconnecting the trailer chassis and the loading ramp.

Rodin, Hunt, Whitlow, and Averette are typical of steering mechanismsfor trailers attachable to the bumper of the prime mover. Averette showsa trailer wheeled dolly with steering arm 56 connected to a bumper ofthe prime mover. Bigge and Lemmon are examples of steering bars usedwith semitrailers. Mannheim is typical of a dollylik'e mechanism usedwith a tractor harrow. 'Isachsen shows a rodlike steering mechanisminvolving a wheeled link and a main member cam plate (1).

SUMMARY OF THE INVENTION According to the present invention, a tow dollyfor wheeled vehicles is provided with a wheeled chassis having its frontconverging as a tongue connectable to a towing vehicle rear bumper andits aft end supporting an axle and a pair of wheels. A pair of towedvehicle wheel ramps are longitudinally pivoted in the aft end of thechassis, so as to serve as an inclined ramp for loading of the towedvehicle under its own power and a confining member for securing thetowed vehicle front wheels, as the vehicle is towedLCompression meansare interposed between the forward end of the wheel ramp and thechassis, so as to dampen the load. Also, locking chains are provided tolock the towed vehicle wheels to the wheel ramp, thus providing use ofthe towed vehicle's suspension system to dampen the load during towing.

BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a fragmentary perspective viewof a towing vehicle pulling a towed vehicle, having its front wheelssecured upon the tow dolly chassis FIG. 2 is a top plan of the tow dollyprior to loading;

FIG. 3 is a longitudinal sectional view taken along section line 33 ofFIG. 2, showing the loading of the towed vehicle upon the inclined wheelramps, pivoted so as to touch the ground;

FIG. 4 is a similar view showing the towed vehicle in place with itsfront wheels chain locked to the front of the ramps, which at their rearends are pivoted clear of the ground;

FIG. 5 is a sectional view taken along section line 5-5 of FIG. 2;

FIG. 6 is a sectional view taken along section line 6-6 of FIG. 2; and

FIG. 7 is an enlarged side elevation of a proposed surge brake assembly.

DESCRIPTION OF THE PREFERRED EMBODIMENTS I In FIG. 1, a towing vehicle20 is shown as pulling tow 26 by means of a ball socket connection 32 toa conventional I bumper hitch 24. The front wheels 36 of towed vehicle22 are,

supported upon a pair of wheel ramps 71-72 longitudinally pivoted in therear of the tow dolly. The tow dolly includes a I 2 surge brakemechanism 34 operatively connected to. the

wheels 37 and a steering linkage mechanism 78 turning these I 7 twodolly wheels 37, relatively to turning of the towing vehi- Asillustrated in FIG.'2, chassis 26 includes a pair of arms 30 convergingforwardly to join a tongue beneath a plate 52 and having at the forwardextremity of tongue 95 a ball socket cup 32 adjustable by means of knob120. At the diverging aft end of arms 30 there is supported a transversechannel 56. Extending rearwardly of channel 56 are a pair of housingelements 92 which support the individual wheel axles 90, as well as thetransverse pivoting bar 68. A pair of identical wheel ramps 71 and 72are pivoted upon bar 68 so that their front at; cuate portion 74 ispresented forwardly of the axles 90 and so that the ramp portion 72 ispresented rearwardly of the entire chassis.

Interconnecting the front arcuate portions 74 is a rectangular bar 54. Apair of identical hydraulic compression elements 58 and 60 are pivotedat one end to the chassis gusset 76 and at their other ends are pivotedto bar 76 by lugs 66.

The towed vehicle 22 may be loaded upon the inclined ramp under its ownpower as illustrated in FIG. 3. In FIG. 4, the vehicle is shown afterbeing loaded, the weight of the front wheels 36 compressing thehydraulic pistons 58 and 60 so that the arcuate portion 74 rests belowthe axles 90 of the dolly wheels 37.

The individual wheels 36 of towed vehicle 22 are locked into the arcuateportions 74 by means of conventional chains 108 secured at their rearends by linking to the upstanding ramp flanges 75. As indicated in FIG.4, the individual chains 108 extend over the tires 36 and at theirforward position are joined to contact chains 62 and 64 which aresecured to channel 56. A conventional chain tightener or tension elementmay be used to lock chains 108, securing wheels 36 in place. As aresult, a portion of the weight of the towed vehicle is transferred tothe towing vehicle 20 rear wheels, and the towed vehicle 22 shocks (notillustrated) absorb a good deal of motion, eliminating the necessity forproviding shocks in the tow dolly.

The linked steering mechanism is particularly illustrated in FIGS. 2, 5,and 6 as including a steering bar 78 extending through aperture 110 inarms 30 and connected via pivot pin 98 at its forward end to link 94.Link 94 is pivoted as at 96 to the chassis tongue 95. Link 94 is pivotedat its other end to adjustable threaded coupler piece 102 which may besecured to a ball socket or like stud extending through the end of hitchbar 40. At its rear end, steering rod 78 is connected to "the front oftoggle link 80 mounted upon bracket 82 secured to the pivot bar 68.Toggle link 80 at its aft end is connected to tie arm 84, transferringrelative turning of the towing vehicle to the individual wheels 37, theturning positions being shown in phantom. As illustrated in FIG. 6, theindividual tie rod 84 is connected to these wheels 37 via link 86secured to the wheels 37 beneath axles 90.

As illustrated in FIG. 7, the surge brake assembly 34 may be of the typeincluding a stationary element 137 secured to the trailer tongue 95 anda sliding housing 138. A shock absorber 124 may be pivoted at one end tostationary element 37 by link 126 and pivoted to the sliding member 138at its other end. A brake-actuating assembly 120 may be supported uponthe sliding housing 138 via a pair of rods 128 and include a centralshaft and clevis member extending to link 126. As the towing vehicledecelerates, housing 138 is slided upon tongue 137, thus pivoting link126 and causing the central shaft to distend and actuate the tow dollybraking mechanism. Also, of course, chassis lights (not illustrated) maybe supported in the tongue assembly.

As will be apparent, the towed car 22 can be driven up ramp 72 whichthen pivots on round frame section 68. As the towed car wheels 36 passover the pivot point, they roll into the wheel wells 74, and the ramppivots slowly against the force of the shocks 58 and 60. Since wheels 37are thus positioned forwardly of the tow dolly wheels 37, a portion ofthe weight of the towed car 22 is transferred to the back wheels oftowing car 22, providing more stability during towing.

Towed car 22 is tied down by means of chains 108, designed similarly toa standard tire chain, and attached at their front to the channel 56 bytension elements connected to chains 62 and 64. This relatively rigidattachment permits the tow dolly and the towed car 22 to pass over bumpsor in and out of driveways without putting the unit in a bind. Byanchoring the towed vehicle wheels 36 to the tow dolly, the towedvehicle floats upon its own spring suspension, eliminating the necessityfor tow dolly springs.

The front wheels 36 of the towed car are carried only 7 or 8 inchesabove the ground, giving good ground clearance with a low center ofgravity. The tow dolly minimizes side drag or sway of the towing car andthus provides a safe, convenient, and inexpensive method of transportingcars or trucks.

Manifestly, the tow dolly ramp structure, surge brake, and steeringmechanisms may be varied without departing from the spirit of theinvention.

We claim:

1. A tow dolly for wheeled vehicles comprising:

A. chassis converging as a tongue having a towing vehicle connector atits forward end and supporting an axle and wheels at its aft end;

B. a pair of wheel ramps longitudinally pivoted adjacent said axle andinwardly of said wheels in said aft end, said wheel ramps having aconcave fore portion adapted for receiving and confining the frontwheels of a towed vehicle.

C. a compression means interposed between the forward end of said rampsand said chassis;

D. a linked steering mechanism supported in said chassis andinterconnecting each dolly wheel and a portion of said towing vehicle,so as to turn said tow dolly wheels relatively to turning of said towingauto; and

E. a surge brake assembly mounted upon said chassis and connected tosaid wheels, so as to break said dolly as the towing vehicledecelerates, including:

i. a main housing;

ii. a shock absorber pivotably connected via a link at one end to saidmain housing;

iii. a sliding assembly slidably supported upon said housing andconnected to said shock absorber at its other end; and

iv. a brake actuator supported upon said sliding mechanism andoperatively contacting said link of said shock absorber, so as toactuate said brake system as said sliding assembly slides upondeceleration of said towing vehicle.

2. A tow dolly for wheeled vehicles as in claim 1, further including:

F. a pivot bar transversely supported in said chassis rearwardly of saidaxle and said wheel ramps being pivoted upon said pivot rod such thatthe confined wheels of the towed vehicle are secured forwardly of theaxle, so as to transfer a portion of the towed vehicle weight from thedolly to the towing vehicle rear wheels.

3. A tow dolly for wheeled vehicles as in claim 2, further including:

G. locking chains having an aft end secured to the aft portion of eachsaid ramp, a mid portion extensible over the towed vehicle front wheelsand front end secured by tension means to said chassis.

4. A tow dolly for wheeled vehicles as in claim 3, said wheel rampsbeing configured so as to support a curvate portion of the towed vehiclefront wheels below the axle of said dolly.

5. A tow dolly for wheeled vehicles as in claim 4, said wheel rampsbeing interconnected at their front ends by a transverse bar.

6. A tow dolly for wheeled vehicles as in claim 5, said compressionmeans for each said wheel ramp including a hydraulic piston assemblypivoted at its lower end to said chassis and pivoted at its upper end tosaid transverse bar interconnecting said wheel ramps.

1. A tow dolly for wheeled vehicles comprising: A. chassis converging asa tongue having a towing vehicle connector at its forward end andsupporting an axle and wheels at its aft end; B. a pair of wheel rampslongitudinally pivoted adjacent said axle and inwardly of said wheels insaid aft end, said wheel ramps having a concave fore portion adapted forreceiving and confining the front wheels of A towed vehicle. C. acompression means interposed between the forward end of said ramps andsaid chassis; D. a linked steering mechanism supported in said chassisand interconnecting each dolly wheel and a portion of said towingvehicle, so as to turn said tow dolly wheels relatively to turning ofsaid towing auto; and E. a surge brake assembly mounted upon saidchassis and connected to said wheels, so as to break said dolly as thetowing vehicle decelerates, including: i. a main housing; ii. a shockabsorber pivotably connected via a link at one end to said main housing;iii. a sliding assembly slidably supported upon said housing andconnected to said shock absorber at its other end; and iv. a brakeactuator supported upon said sliding mechanism and operativelycontacting said link of said shock absorber, so as to actuate said brakesystem as said sliding assembly slides upon deceleration of said towingvehicle.
 2. A tow dolly for wheeled vehicles as in claim 1, furtherincluding: F. a pivot bar transversely supported in said chassisrearwardly of said axle and said wheel ramps being pivoted upon saidpivot rod such that the confined wheels of the towed vehicle are securedforwardly of the axle, so as to transfer a portion of the towed vehicleweight from the dolly to the towing vehicle rear wheels.
 3. A tow dollyfor wheeled vehicles as in claim 2, further including: G. locking chainshaving an aft end secured to the aft portion of each said ramp, a midportion extensible over the towed vehicle front wheels and front endsecured by tension means to said chassis.
 4. A tow dolly for wheeledvehicles as in claim 3, said wheel ramps being configured so as tosupport a curvate portion of the towed vehicle front wheels below theaxle of said dolly.
 5. A tow dolly for wheeled vehicles as in claim 4,said wheel ramps being interconnected at their front ends by atransverse bar.
 6. A tow dolly for wheeled vehicles as in claim 5, saidcompression means for each said wheel ramp including a hydraulic pistonassembly pivoted at its lower end to said chassis and pivoted at itsupper end to said transverse bar interconnecting said wheel ramps.